Soil acidifier should be relatively cheap. 5 pounds should have been less than $10 usd. For the farm 100 pound bags of sulfur are less than $75 each. Though you do have to buy more than one at a time. (minimum wholesale)
Calcium sulfate - gypsum - is even cheaper than sulfur. Explore alternate sources if you think they are expensive.
Juniper and JBP do not need particularly acidic soils. I would keep my dose here at the lower end of the range they give you.
from off the top of my head:
Only Japanese maple, ume, nanking cherry, & jasmine would benefit from mildly acidic soil. And of the garden plants
only Eugenia, persimmon, lavender star flower, guava, lemon, and bromeliad would prefer mildly acidic soil. All of these would be fine with a acidity appropriate for Satsuki azalea. Most of these will tolerate more alkaline conditions than the azalea would. For most of North America - I would say most people would not need to adjust the pH of their soils for these trees.
all the rest would tolerate mildly acidic to mildly alkaline soils.
I know nothing about the needs of Loquat (Biwa).
Do you have a unique problem that requires you to worry about alkalinity? Unusually high total Alkalinity water? Unusual soils in the area where dust blowing onto trees is aggressively alkaline? (like downwind of a cement storage silo). What are you using as your potting media? Anything unusual in the mix?
A lot of total alkalinity issues, can be taken care of by designing your potting mix to go with your irrigation water. Remember the real issue is total alkalinity, the amount of Calcium available in the water and the soil, not the actual pH. Focusing on pH is a ''red herring'', you should focus on the total calcium content of your water, and the CEC of your media components.
If you have high calcium content water, setting up a rain water collection system can go a long way to solving the problem, as rain water is low calcium. Adding a larger portion of fir bark or pine bark to your mix will help due to higher CEC of the bark as it decomposes in the mix.
Blueberries are fairly extreme calcifuges, meaning they really hate excess calcium in the soil or water. They need pH far lower, more acidic than Satsuki azalea. For them the standard potting mix is 2 parts bark, one part Canadian peat moss (including the fines), and less than 10 % of the total volume of media add hardwood sawdust. The sawdust is to feed the mycorrhiza the blueberries depend on. This blend when watered with low to moderate calcium content water (total alkalinity less than 225 mg/liter as calcium carbonate) will create a potting media that is between pH 5.0 to 6.0, You can add a fair amount of an inert component like perlite to keep it from compacting.
But in general, do you really need to be worrying about soil pH? do other bonsai growers in your area have a problem? To fruit tree growers in your area have a problem?